In general, when a digital signal is recorded on and reproduced from a tape-like recording medium such as a magnetic tape by a rotating head, the digital signal is recorded and reproduced in data blocks. On the other hand, at trick play reproduction (special reproduction) that reproduces a digital signal at a speed different from that of recording, a rotating head scanning track on a tape-like recording medium unlike at normal reproduction, traverses diagonally a recording track, reproduces in data blocks only a track existing recording signal recorded by a rotating head with the same azimuth angle as a reproducing rotating head; therefore, head output viewed with a time axis is reproduced in burst form at regular intervals, making it difficult to obtain a trick play reproducing signal.
For this reason, a digital signal recording method that permits trick play reproduction is known, by converting a trick play reproducing digital signal into a normal reproducing digital signal to locate and record on a rotating head scanning track at trick play reproduction, on a track on which a normal reproducing digital signal is conventionally recorded (e.g. Japanese Patent Laid-Open No. 261278/1994: Title of the Invention "A Signal Recording and Reproducing Apparatus").
However, cumulation of the amount of data recorded on the tape-like recording medium is fixed in the above conventional digital signal recording method; therefore, to record a trick play reproducing digital signal (also hereinafter called special reproducing data), reserving a constant amount of area forces the rest to be a data area for recording and reproducing a normal reproducing digital signal (also hereinafter called normal reproducing data).
The recorded amount of special reproducing data is fixed in the above conventional digital signal recording method; therefore, when a normal reproducing data transmission rate which is different depending on the contents of information, broadcasting system and so on, is high, the fixed recorded amount of special reproducing data restricts recording of the essentially necessary amount of normal reproducing data.
Further, FIG. 1 shows an example of a track pattern for fast reproduction as trick play. In the same diagram, the diagonally shaded portions on main data areas are fast-reproducing digital signal (fast-reproducing data) recording portions; and the other blank portions are normal reproducing digital signal (normal reproducing data) recording portions. As shown in the same diagram, this track pattern shows a pattern where 6-fold speed fast-reproducing data is located in two areas within each track recorded by a rotating head with the same azimuth angle; and the same data is multiplexed and recorded six times in tracks recorded horizontally by a rotating head with the same azimuth angle.
Use of phase control in two tracks at reproduction for a magnetic tape with this track pattern, to start a head trace in relation to a constant phase for a given track on which fast-reproducing data is recorded, can reproduce all necessary data, even if head scanning is started with any track (this recording and reproducing method is called "phase lock").
Also this track pattern can reproduce these fast-reproducing data at an approximately 1- to 2-fold speed, and 3- to 4-fold speed. In this case, the reproducing rate in n-fold speed (n&lt;6) is n/6 for a 6-fold speed reproducing rate. FIG. 1 represents a 3-fold speed head scanning track as 3x; and a 6-fold speed head scanning track as 6x.
The above conventional digital signal recording and reproducing method, locating the same special reproducing data repeatedly, has no good recording efficiency. In addition, because a relatively many fast-reproducing data record areas are needed, the sufficient number of normal reproducing data record areas cannot be obtained on a magnetic tape with the limited amount of recorded data. This causes a problem, especially for recording a low bit rate application in a slow tape mode such as a long-time mode, occurring in circumstances when normal reproducing data areas must be reserved to some extent, even though a fast-reproducing data areas occupy a physically constant percentage on the magnetic tape.
A conventional method is also known in such a way that a head trace start track is determined in some way; e.g. a 6-fold speed fast-reproducing data is located and recorded on one head scanning track at the speed rate; a head trace is started in relation to one particular phase through reproducing phase control; and head scanning is begun from the determined track to reproduce 6-fold speed data (this recording and reproducing method is called "track select").
Since this recording and reproducing method does not record doubly the same fast-reproducing data, it has good record efficiency and minimizes the number of fast-reproducing data record areas; therefore, many normal reproducing data record areas can be obtained on a magnetic tape with the limited amount of recorded data. However, there is a problem that it takes long time to start fast reproduction, because all necessary data cannot be recorded, unless the head scanning is started from the determined track.
An object of the invention in view of the above points, is to offer a digital signal recording method and recording apparatus that can record the necessary amount of normal reproducing data as well as normal reproducing data and special reproducing data on a tape-like recording medium with an efficient sharing against all data areas, and further a recording medium recorded with this recording method.
Another object of the invention is to offer a digital signal recording method and recording apparatus that can reserve the necessarily minimized number of normal reproducing data areas to start quickly fast reproduction, by controlling variably fast-reproducing data record areas according to the data rate of normal reproducing data, and further a recording medium recorded with this recording method.